ProfilerStore.js — react Source File

Source Code

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

import EventEmitter from '../events';
import {prepareProfilingDataFrontendFromBackendAndStore} from './views/Profiler/utils';
import ProfilingCache from './ProfilingCache';
import Store from './store';
import {logEvent} from 'react-devtools-shared/src/Logger';

import type {FrontendBridge} from 'react-devtools-shared/src/bridge';
import type {ProfilingDataBackend} from 'react-devtools-shared/src/backend/types';
import type {
  CommitDataFrontend,
  ProfilingDataForRootFrontend,
  ProfilingDataFrontend,
  SnapshotNode,
} from './views/Profiler/types';

export default class ProfilerStore extends EventEmitter<{
  isProcessingData: [],
  isProfiling: [],
  profilingData: [],
}> {
  _bridge: FrontendBridge;

  // Suspense cache for lazily calculating derived profiling data.
  _cache: ProfilingCache;

  // Temporary store of profiling data from the backend renderer(s).
  // This data will be converted to the ProfilingDataFrontend format after being collected from all renderers.
  _dataBackends: Array<ProfilingDataBackend> = [];

  // Data from the most recently completed profiling session,
  // or data that has been imported from a previously exported session.
  // This object contains all necessary data to drive the Profiler UI interface,
  // even though some of it is lazily parsed/derived via the ProfilingCache.
  _dataFrontend: ProfilingDataFrontend | null = null;

  // Snapshot of all attached renderer IDs.
  // Once profiling is finished, this snapshot will be used to query renderers for profiling data.
  //
  // This map is initialized when profiling starts and updated when a new root is added while profiling;
  // Upon completion, it is converted into the exportable ProfilingDataFrontend format.
  _initialRendererIDs: Set<number> = new Set();

  // Snapshot of the state of the main Store (including all roots) when profiling started.
  // Once profiling is finished, this snapshot can be used along with "operations" messages emitted during profiling,
  // to reconstruct the state of each root for each commit.
  // It's okay to use a single root to store this information because node IDs are unique across all roots.
  //
  // This map is initialized when profiling starts and updated when a new root is added while profiling;
  // Upon completion, it is converted into the exportable ProfilingDataFrontend format.
  _initialSnapshotsByRootID: Map<number, Map<number, SnapshotNode>> = new Map();

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